Windowsでネットワークアダプターの情報を得る

1. はじめに

Windows で ipconfig の実行結果みたいな情報をCで書くとどうなのだろう、と思って調べました。自分用メモ。

GetAdaptersAddresses がまぁ便利な関数ですね。

2.コード

sample.cpp

#include    <stdio.h>
#include    <locale.h>

#include    <winsock2.h>
#include    <ws2tcpip.h>
#include    <iphlpapi.h>

#pragma comment(lib, "iphlpapi.lib")

void print_ip_addresses(PIP_ADAPTER_ADDRESSES pAdapter) {
    PIP_ADAPTER_UNICAST_ADDRESS pUnicast = pAdapter->FirstUnicastAddress;
    while (pUnicast) {
        char ipAddress[INET6_ADDRSTRLEN] = { 0 };
        DWORD ipAddressLen = INET6_ADDRSTRLEN;

        if (pUnicast->Address.lpSockaddr->sa_family == AF_INET) {
            // IPv4アドレス
            struct sockaddr_in* sa_in = (struct sockaddr_in*)pUnicast->Address.lpSockaddr;
            inet_ntop(AF_INET, &(sa_in->sin_addr), ipAddress, ipAddressLen);
        }
        else if (pUnicast->Address.lpSockaddr->sa_family == AF_INET6) {
            // IPv6アドレス
            struct sockaddr_in6* sa_in6 = (struct sockaddr_in6*)pUnicast->Address.lpSockaddr;
            inet_ntop(AF_INET6, &(sa_in6->sin6_addr), ipAddress, ipAddressLen);
        }

        printf("IP Address: %s\n", ipAddress);
        pUnicast = pUnicast->Next;
    }
}

int main()
{
    setlocale(LC_ALL, "japanese");

    DWORD dwSize = 0;
    PIP_ADAPTER_ADDRESSES pAddresses = NULL, pAdapter = NULL;

    // 必要なバッファサイズを取得
    if (GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, NULL, &dwSize) == ERROR_BUFFER_OVERFLOW) {
        pAddresses = (PIP_ADAPTER_ADDRESSES)malloc(dwSize);
    }
    if (pAddresses == NULL) {
        printf("メモリの確保に失敗しました。\n");
        return 1;
    }

    // アダプター情報を取得
    if (GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, pAddresses, &dwSize) == NO_ERROR) {
        pAdapter = pAddresses;
        while (pAdapter) {
            printf("Adapter Name: %ls\n", pAdapter->FriendlyName);
            printf("MAC Address: ");
            for (DWORD i = 0; i < pAdapter->PhysicalAddressLength; i++) {
                printf("%02X", pAdapter->PhysicalAddress[i]);
                if (i < pAdapter->PhysicalAddressLength - 1) printf("-");
            }
            printf("\n");
            print_ip_addresses(pAdapter); // IPアドレス出力
            printf("\n");
            pAdapter = pAdapter->Next;
        }
    }
    else {
        printf("アダプター情報の取得に失敗しました。\n");
    }

    // メモリ解放
    free(pAddresses);

    return 0;
}